An X-ray tube used in an X-ray generator is provided with a filament and a target disposed with space between one another, for example. By applying a high voltage between the filament and the target, it is possible to cause thermal electrons discharged from the filament to collide with the target so as to generate X-rays from the target.
In such an X-ray generator, the target generates heat in step with the generation of X-rays, so a mechanism capable of cooling the target using a cooling medium is sometimes used (for example, see Patent Document 1 below). In addition to liquids such as cooling water, gases such as air are also used as cooling mediums. For example, in an X-ray generator which generates X-rays with a few kW of power, a water cooling system for cooling the target using cooling water may be used, and in an X-ray generator which generates X-rays with power up to several 100 W, an air cooling system for cooling the target using air may be used.
FIG. 5 is a schematic diagram illustrating an example of the configuration of an X-ray analyzer provided with a conventional X-ray generator 101. The X-ray generator 101 is provided with an X-ray tube 111, a high-voltage power supply 112, a cooling water circulator 113, and the like.
Power is supplied to the X-ray tube 111 from the high-voltage power supply 112, and a high voltage is applied between a filament and a target, neither of which is illustrated. As a result, thermal electrons discharged from the filament collide with the target, and X-rays are generated from the target. The target, which generates heat in step with the generation of X-rays, is cooled using cooling water circulated within piping 114 by the cooling water circulator 113.
This X-ray analyzer is a fluorescent X-ray analyzer (XRF), which uses a detector 102 to detect fluorescent X-rays generated by irradiating a sample S with X-rays from the X-ray generator 101 so that the sample S can be analyzed based on the detection result. The fluorescent X-rays generated from the sample S are split by a spectroscope 103 comprising a spectroscopic crystal, and the intensities of specific wavelengths are measured with the detector 102.
The spectroscopic characteristics of this spectroscope 103 are dependent on the surface spacing of the spectroscopic crystal, the positional relationship of the spectroscope 103 with respect to the sample S and the detector 102, or the like. Therefore, when the spectroscope 103 expands or contracts based on changes in ambient temperature, there is a risk that the spectroscopic characteristics may change so that analysis cannot be performed with high precision. Therefore, in the example of FIG. 5, the spectroscope 103 can be heated with a heater 104.
Specifically, the heater 104 and a temperature sensor 105 are disposed inside a spectroscopic chamber 106 together with the spectroscope 103, and the temperature inside the spectroscopic chamber 106 is kept constant by controlling the driving of the heater 104 with a temperature controller 107 based on the temperature inside the spectroscopic chamber 106 detected by the temperature sensor 105. As a result, it becomes possible to prevent the spectroscope 103 from expanding or contracting based on changes in ambient temperature, which makes it possible to perform analysis with high precision.